The proposal is already receiving pushback from some senators and the likelihood of it being passed by both chambers is deemed slim by supporters and opponents alike.

The ban is part of a slew of legislation introduced in the aftermath of the shootings in Newtown, Conn. and recommended by President Barack Obama. But even Senate Majority Leader Harry Reid (D-Nev.) has expressed doubt that the assault weapon ban could be approved by the Senate.

In an emotional press conference on Thursday, a number of Democratic members of Congress spoke in favor of the legislation, echoed by victims of previous mass shootings.

“These massacres don’t seem to stop, they continue on,” Feinstein said, with three display boards covered in assault weapons at her side. “Each gunman used a semi-automatic assault weapon or large-capacity magazine.”

Sen. Chuck Schumer (D-N.Y.) argued that limitations on assault weapons were well within the powers of Congress, likening assault weapons to screaming fire in a crowded movie theater.

“It comes down to this: Assault weapons were designed for and should be used on our battlefields, not on our streets,” Schumer said. He added, “There is no inalienable right to own and operate 100-round clips on AR-15 assault rifles.”

Sen. Chris Murphy (D-Conn.), who represented Newtown, Conn. as a member of the House, made an emotional appeal for the ban.

“Kids would be alive today if the law we are proposing today was in place,” Murphy said.

Rep. Elizabeth Esty (D-Conn.) told the story of a victim in the Sandy Hook Elementary shooting who called her husband minutes before to say the gunman was headed her direction.

“What does it take? What does it take for us as a nation to act?” Esty said. “I hope, I pray and I believe that this horror in the little town of Newtown, Conn. is our wake-up call. It is our call as Americans to act and to act now to save lives.”

After the politicians spoke, a procession of shooting victims, from Tucson, Ariz., to Virginia Tech took the microphone to tell their stories and advocate for the law.

The unveiling of the assault weapons ban also drew quick opposition.

“Senator Feinstein has been trying to ban guns from law-abiding citizens for decades,” the National Rifle Association said in a statement. “It’s disappointing but not surprising that she is once again focused on curtailing the Constitution instead of prosecuting criminals or fixing our broken mental health system.”